I. Field of the Invention
This invention relates generally to the components of a manhole structure and more particularly relates to components utilized in the base of a manhole system including an invert liner formed or positioned within the base thereof. The replaceable extension collar of the present invention is adapted for sealable engagement with the invert liner and is suitable for use in either new construction or rehabilitation of the manhole structure.
II. Discussion of the Prior Art
Sanitary and storm systems generally comprise a plurality of networked pipelines. These pipelines typically pass through or join together at a manhole or catch basin structure. The manhole or catch basin structure serves as a node for the sewer or drainage system and also provides access for inspection. A manhole or catch basin structure typically includes a base having concentric inner and outer side walls extending upward, a cone which rests on top of the base, adjusting rings which rest on top of the cone, a support frame, and a cover or grate that is placed on top of the support frame. The base and cone of the manhole structure is typically constructed of a mortared block or casted concrete and is susceptible to erosion over time.
Fluids passing through the manhole structure tend to deteriorate the portion of the manhole system that is in direct or causal contact with the fluids. These fluids may include sewage and putrid water, which are very acidic and may comprise hydrogen sulfide and sulfuric acid. Over time, exposure to sewage, putrid water, or the gases emitted therefrom may damage the concrete of the canal bed, base, and cone. Also, in catch basins, road salt may also deteriorate the concrete base of the catch basin. This is due to the eventual breakdown of the concrete by the road salt, especially if the concrete is of poor quality. When repair or replacement of these manhole or catch basin structures is required, due to a deteriorated canal bed, base or cone, the procedure is extremely expensive, time consuming, difficult, and may even require excavation and removal of some or all of the manhole structure.
Although manhole base polymer liners have been provided for lining the canal bed of the base, these liners typically terminate in the bottom portion of the base and at least a portion of which is embedded in the base itself. Although a majority of the fluid passing through the manhole or catch basin is in direct contact with the liner, a small amount of the fluid may contact the sidewalls of the base. Over time this minimal contact with the sidewalls may cause damage to the sidewalls of the base. Hence, there is a need for a replaceable device suitable for protecting the base side walls from the corrosive nature of the fluids passing there through, which may be utilized in either new construction or rehabilitation of the manhole or catch basin structure. The present invention meets these and other needs that will become apparent from a review of the description of the present invention.